A1200 scart lead picture wobble

WDeranged · 20 March 2010, 16:31

I've just got my A1200 (from amigakit) home and connected it to my Sony LCD TV via the RGB scart lead I bought with it and I'm getting really bad picture instability like ripples constantly shifting.

I've been testing the Amiga on an old CRT tv previously and apart from the picture turning green every time the computer changed screen modes (correctable by reconnecting the scart lead) the picture was flawlessly stable.

The TV is a Sony KDL-40 V4000 from last year.

Any ideas?

WDeranged · 20 March 2010, 16:53

I've just tested it on my crt portable and it looks absolutely fine, I've also played around with every setting on my Sony with no joy

Toni Wilen · 20 March 2010, 17:20

Do interlaced modes have same problems?

Djay · 21 March 2010, 00:01

recently bought a 22" Samsung LCD and connected new A1200 via RGB scart, of course on a larger screen the wobble would probably be worse, but it is still noticeable on a 22

i played around with the controls

setting to 4:3, using natural colour, for some reason turning down the sharpness to 0-5 fixed most of the wobble to an "ok" level... it seems to move white edge lines behind the black lines..

playing games etc isnt too bad at all, using workbench and apps tend to show wobble more, static screens can be bad

strangely, i have turned it on and the wobble has gone and its sharp, then the wobble starts...

i have also got an old A600 connected via composite, the screen is solid but its blurry (what you would expect)

i have turned everything off in my house ie wifi, high power devices (could of been interference picked up on the cable (they are never shielded enough)

i think its more to do with refresh rates on LCD

has anyone tried a cheap VGA adaptor and LCD screen?

alexh · 21 March 2010, 01:04

Most likely to be an incorrectly / partially wired SCART cable. CRT's are very tolerant to incorrect voltages on certain SCART inputs and missing grounds because they drive analog circuitry whereas modern LCD/Plasma displays feed into a digitising system.

Examine your SCART cable wiring and use the diagram created by Ian Steadman for reference. Pay special attention to the values of the resistors used and the number of grounds connected at the SCART end.

http://eab.abime.net/showpost.php?p=592491&postcount=1

Djay · 21 March 2010, 02:15

i am never gonna be able to do that, could anyone make up a good RGB scart fixed wiring cable for me i would buy NOW!

i need 2

WDeranged · 21 March 2010, 03:13

Djay's problem sounds exactly the same as mine, I got my scart lead from Amigakit, I really don't have the technical skill to compare it to the diagram though.

http://amigakit.leamancomputing.com/...roducts_id=226

WDeranged · 21 March 2010, 03:58

After reading the thread alexh pasted It does sound very much like this cable is wired incorrectly, another user appears to have had the same issue with a cable he got from Ebay.

alexh · 21 March 2010, 14:43

If you just bought your SCART cable from Amigakit ask them about it and see if they can correct the problem. They seem to be nice guys so I imagine a few solders and resistor changes would not be too hard for them.

If they don't, insist on returning it for a full refund. I am sure you'd be entitled to one.

Djay · 21 March 2010, 18:23

amigakit guys post here quite a bit, so maybe they could respond here

i bought my cable from ebay, but if amigakit.com could fix the cable first i would buy another one from them!!!

20 March 2010, 16:31	#1
WDeranged Registered User Join Date: Sep 2009 Location: Staffs, UK Posts: 55	A1200 scart lead picture wobble I've just got my A1200 (from amigakit) home and connected it to my Sony LCD TV via the RGB scart lead I bought with it and I'm getting really bad picture instability like ripples constantly shifting. I've been testing the Amiga on an old CRT tv previously and apart from the picture turning green every time the computer changed screen modes (correctable by reconnecting the scart lead) the picture was flawlessly stable. The TV is a Sony KDL-40 V4000 from last year. Any ideas?

21 March 2010, 03:58	#8
WDeranged Registered User Join Date: Sep 2009 Location: Staffs, UK Posts: 55	After reading the thread alexh pasted It does sound very much like this cable is wired incorrectly, another user appears to have had the same issue with a cable he got from Ebay. Last edited by WDeranged; 21 March 2010 at 04:40.

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20 March 2010, 16:53	#2
WDeranged Registered User Join Date: Sep 2009 Location: Staffs, UK Posts: 55	I've just tested it on my crt portable and it looks absolutely fine, I've also played around with every setting on my Sony with no joy

20 March 2010, 17:20	#3
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,506	Do interlaced modes have same problems?

21 March 2010, 00:01	#4
Djay 95th User Join Date: May 2001 Location: Brighton/UK Age: 48 Posts: 3,120	recently bought a 22" Samsung LCD and connected new A1200 via RGB scart, of course on a larger screen the wobble would probably be worse, but it is still noticeable on a 22 i played around with the controls setting to 4:3, using natural colour, for some reason turning down the sharpness to 0-5 fixed most of the wobble to an "ok" level... it seems to move white edge lines behind the black lines.. playing games etc isnt too bad at all, using workbench and apps tend to show wobble more, static screens can be bad strangely, i have turned it on and the wobble has gone and its sharp, then the wobble starts... i have also got an old A600 connected via composite, the screen is solid but its blurry (what you would expect) i have turned everything off in my house ie wifi, high power devices (could of been interference picked up on the cable (they are never shielded enough) i think its more to do with refresh rates on LCD has anyone tried a cheap VGA adaptor and LCD screen?

21 March 2010, 01:04	#5
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,337	Most likely to be an incorrectly / partially wired SCART cable. CRT's are very tolerant to incorrect voltages on certain SCART inputs and missing grounds because they drive analog circuitry whereas modern LCD/Plasma displays feed into a digitising system. Examine your SCART cable wiring and use the diagram created by Ian Steadman for reference. Pay special attention to the values of the resistors used and the number of grounds connected at the SCART end. http://eab.abime.net/showpost.php?p=592491&postcount=1

21 March 2010, 02:15	#6
Djay 95th User Join Date: May 2001 Location: Brighton/UK Age: 48 Posts: 3,120	i am never gonna be able to do that, could anyone make up a good RGB scart fixed wiring cable for me i would buy NOW! i need 2

21 March 2010, 03:13	#7
WDeranged Registered User Join Date: Sep 2009 Location: Staffs, UK Posts: 55	Djay's problem sounds exactly the same as mine, I got my scart lead from Amigakit, I really don't have the technical skill to compare it to the diagram though. http://amigakit.leamancomputing.com/...roducts_id=226

21 March 2010, 14:43	#9
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,337	If you just bought your SCART cable from Amigakit ask them about it and see if they can correct the problem. They seem to be nice guys so I imagine a few solders and resistor changes would not be too hard for them. If they don't, insist on returning it for a full refund. I am sure you'd be entitled to one.

21 March 2010, 18:23	#10
Djay 95th User Join Date: May 2001 Location: Brighton/UK Age: 48 Posts: 3,120	amigakit guys post here quite a bit, so maybe they could respond here i bought my cable from ebay, but if amigakit.com could fix the cable first i would buy another one from them!!!

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